On average, listings lease in the $10's per square foot per year. The Iowa City region is going through a a boost in rates. In the last 3 months, the median rate went up $2 per sqft per year. That's a 10% increase in rent.
In the last 90 days, 24 listings have come on the market, which means office spaces most likley are leasing quickly. You'll want to be prepared to make an offer immediately. About 33% of the available leases in the Iowa City are subleases, so you might be able to snag a great spot on a short term. There aren't many listings below 2,000 square feet on the market, so finding a space for a small business might be tough.
The standard measurement for office space in this area is around 1,190 sqft. Most properties in this market are approximately 2 stories. Most buildings in this area were built in 1989 and are Class A.